1. Field of the Invention
The present embodiments relate to a thin film transistor (TFT), a flat panel display having the TFT and a method for manufacturing the TFT and the flat panel display; and more particularly, to a thin film transistor (TFT) having a transformed region in an organic semiconductor layer that provides the same result as patterning the organic semiconductor layer, a flat panel display having the TFT and a method for manufacturing the TFT and the flat panel display.
2. Description of the Related Art
A thin film transistor (TFT) has been used in a flat panel display as a switching element for controlling operations of each pixel or as a driving element for operating a pixel. The TFT includes a liquid crystal display element, an organic electroluminescent display element and an inorganic light emitting display element.
The TFT includes an active layer having a source region and a drain region which are doped with a high concentration of impurity and a channel region formed between the source region and the drain region. The TFT also includes a gate electrode formed on a predetermined region of a substrate where the channel region is faced and the gate electrode is insulated from the active layer. The TFT further includes a source electrode coupled to the source region and a drain electrode, each coupled to the drain region.
The flat panel display has become thinner and has been required to have flexibility.
For manufacturing thinner flat panel displays having flexibility, a plastic substrate has been used as a substrate of the flat panel display instead of a glass substrate. When using a plastic substrate, a high temperature thermal process cannot be performed in manufacturing the flat panel display. Accordingly, there are difficulties in using a conventional polysilicon thin film transistor for manufacturing the flat panel display.
To overcome the above problem, an organic semiconductor has been used. The organic semiconductor can be formed in a low temperature thermal process for manufacturing a thin film transistor (TFT) which is relatively inexpensive.
However, a photo lithographing method cannot be used for patterning the organic semiconductor layer. In other words, the pattern is formed on the organic semiconductor forming an active channel. If a combination method of a wet type and a dry type of etching methods is used for forming the pattern on the organic semiconductor, the organic semiconductor is damaged.
Therefore, a new method for patterning the organic semiconductor is needed.